Drag and drop the contents of the folder into your Rift/Interface/Addons folder; overwrite all files when upgrading. The default location for this is in your Documents folder.

How to use:

Left-Click and Hold to drag the window around to your desired location.

Right-Click the RareNerd window to display a drop down of all the Zones. From there, select the zone that you are either in or interested at looking at to either find out the coordinates or if you killed a rare mob shown in green or have not killed shown in red. You can navigate through the selected zone rare mobs by using the left or right arrows.

Commands: Use /rarenerd or /rn [option] to type any of the following, for example: /rarenerd show